/* subst.c -- 在字符串中替换 */

#include <stdio.h>

#define PSQR(x) printf("The square of " #x " is %d.\n", ((x)*(x)))

int main(void)
{
    int y = 5;

    PSQR(y);
    PSQR(2 + 4);

    return 0;
}